Developments in database technology have yielded increased capabilities with respect to data organization, data management, and data storage for various computer applications. In recent years, database storage capacity has gradually increased, and various operations performed by users on a database have also become more and more complex and frequent. Thus, ensuring that the database quickly returns a result desired by a user within an expected response time has become a hot study topic in the database field.
In existing database management systems (DBMSs), database indexing technology has been widely applied. A database index is a structure that sorts values in one or more columns of a database table. With an index, particular information in the database table may be quickly accessed. A database index may greatly accelerate the response speed of a query operation. However, it may also cause some negative impacts despite the above-mentioned improvements in query performance.
Further, when performing a data manipulation operation (i.e., data manipulation language (DML) operations, such as insert, delete, and modify) on the database table, it might be necessary to update the index. In this event, the database management system has to modify the data in various tables of the database, as well as update the index impacted by the DML operation. In other words, this DML operation can be deemed as complete only after both the table in the database and the impacted index have been successfully updated. If only the table in the database has been successfully updated while the impacted index has not been updated yet, the index cannot accurately reflect the actual state of the database. Thus, if a query is performed on an index that has not been completely updated, the returned result might be inconsistent with the latest data stored in the database. For a large database, its index may have a quite complex data structure; thus, the time spent on updating the index may have an adverse impact on the response time of the database.